Invasive seaweed spreads throughout New England

Monday

Dec 24, 2012 at 12:01 AM

PORTLAND, Maine — A fast-growing, fast-spreading Asian seaweed that's crowded out native species, fouled beaches and made a mess of lobster traps in Massachusetts has spread north to Maine and south to New York.

By CLARKE CANFIELD

PORTLAND, Maine — A fast-growing, fast-spreading Asian seaweed that's crowded out native species, fouled beaches and made a mess of lobster traps in Massachusetts has spread north to Maine and south to New York.

First discovered on a Rhode Island beach in 2009, the invader doesn't pose a public health threat, but can create a stinky muddle as it did earlier this year when it washed onto beaches in Massachusetts. The red seaweed gives off a putrid odor when it dries and decays.

Native to the Pacific Ocean, the seaweed probably came to the U.S. in ballast water in a ship from Europe, where it first showed up in 1984 along the French coast, said Matt Bracken, a biologist with Northeastern University in Boston. In Europe, the seaweed can now be found from Norway to the Mediterranean.

Bracken said he wouldn't be surprised if the seaweed has already reached Canada.

"I would estimate it could probably survive for parts of the year from North Carolina to Newfoundland," he said.

Heterosiphonia japonica creates problems for lobstermen.

Last spring, the plant clung to the sides of Skip Ryan's gear and clogged his traps to the point where he was forced to move his traps from inner Boston Harbor into deeper waters, where the seaweed wasn't so bad.

When Ryan reached inside the traps to remove the seaweed, it would break apart in his fingers, creating a nasty mess. Some of his traps became so weighted down with the stuff that it was hard for him to pull them aboard.

"It gets all over the ground line, it's all over the wheelhouse of the boat, it's all over the pot hauler," he said. "The stuff is horrendous."

Some are concerned the seaweed could squeeze out native varieties and smother seagrass beds, which serve as important nursery grounds for fish, lobsters and other marine species.

"People shouldn't be concerned from a public health standpoint," Bracken said. "But any time diversity is impacted in an ecosystem, it has potential consequences for the functioning of that system."

When Massachusetts beaches from Cape Cod to Cape Ann were blanketed with seaweed, they looked like they had been spread with cranberry sauce. Public works departments had to plow and rake up the mess and take the seaweed to landfills or bury it under the sand.

Mike Collins, who heads the Beverly public works department, said the agency got repeated calls from residents complaining that a sewer line must have broken because the smell was so foul. It turned out the odor was coming from seaweed that had washed up in gooey piles on a private beach.